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F. KUHN AND L. H. THOMAS.

ELECTRIC SOLDERING IRON.

APPLICATION men MAR. 20. 1922.

Patented Aug. 15; 1922.

H mum N W 2 M a w M W L UNITED STATES PATENT OFFICE.

t FRANK KUHN AND LAWRENCE H. THOMAS, OF DETROIT, MICHIGAN, ASSIGNORS TOAMERICAN ELECTRICAL HEATER COMPANY, OF DETROIT, MICHIGAN, A. CORPO-BATION OF MICHIGAN,

ELECTRIC SOLDERING IRON.

Specification of Letters Patent. Patented A no, 15, 1922 Applicationfiled March 20, 1922. Serial No. 545,061.

To all whom it may concern:

Be it known that we, FRANK KUHN and LAWRENCE H. THOMAS, both citizens ofthe United States of America, residing at Detroit,'in the county ofWayne and State of Michigan, have invented certain new and usefulImprovements in Electric Soldering Irons, of which the following is aspecification, reference being had therein to the ac companyingdrawings,

The inven'tion relates to electric soldering irons of that type shown inPatent 1,214,186 in which atubular body for receiving the solderingpoint is surrounded with an insulated resistor. The terminals of thisresistor are passed outward from one end of the body through a hollowhandle to which the current supplying conductors are attached. It is theobject of the present invention to provide an improved terminalconstruction which avoids certain defects in the constructionsheretofore used. Thus it is usualto wrap the tubular body or core withmica insulation on which a resistor ribbon is wound. To pass this ribbonout through the handle it is folded so as to make a substantially rightangle turn and this folding, by increasing the thickness places anadditional stress upon the-mica ad acent thereto. Consequently there isdanger of the insulation I breaking down and forming a short circuitbetween the resistor and the metallic core.

To overcome the difficulties just described, we have placed within theend of the body orcore an insulator block insert over which the terminalportion of the resistor ribbon is passed at the point where it is foldedto extend outward. Also, this insulator block is formed with aperturesthercthrough for the passage of the resistor terminal, with the re sultthat danger of breaking down of the insulator is effectually avoided.The invention further consists in certain specific features of theconstruction as hereinafter set forth.

In the drawings:

Figure 1 is an elevation of the soldering iron;

Figure 2 is a sectional elevation;

Figure 3 is also a sectional elevation with a section on line 3-3 ofFigure 2;

Figure 4 is a perspective view of the end portion of the core; and

Figure 5 is a similar view of the insulator insert.

A is the soldering point; B is a tubular heaterjin which the shankportion of the point is inserted, and C is the hollow handle shankthrough which the terminal connections for the heater ass outward to thehandle (not shown). The core member D is provided at its inner end witha flange E and beyond this flange with a threaded bifurcated shankF, forengagement with a nut G for clamping the outer casing H of the heater.Surrounding. the core D is a wrappin I of insulating material such asmica and surrounding this insulation is wound the resistor ribbon J,which is folded at K to extend at right angles outward through thehollow handle. Instead, however, of extending the core member Duninterruptedly to the flange E, it is centrally cut away for thereception of an insulator block L. This block has a portion M forming acomplementary se ment of the cylindrical core .D, also a portion Nforming a complementary segment of the flange E, and a portion 0extending outward beyond said flange between the furcations F. The blockis also rovided withobliquely extending. channels l which pass throughthe flange M from diametri rally opposite sides thereof and terminate atpoints adjacent to the center of the block at the outer end thereof. Theblock is locked in engagement with the core b suitable means such as thecross pin Q which retains.

it from displacement in any direction.

In forming the heater the insulator wrapping I extends not only aroundthe metallic core, but also the portion M of the block L and the firstconvolution of the resistor extends overthis ortion of the block andthen is folded at I to extend at right angles through the channel P. Theopposite ends of the resistor thus pass from opposite sides of the blockthrough the channels P and out ward therefrom adjacent to each other,preferably passing into a double channel insu lator tube R, whichextends outward through the hollow handle. The construction is thereforeone in which all danger of brcalc ing down of the insulation at thepoint of closing of the resistor is avoided, for there is, in additionto the mica insulation, the insulation of the block L. Also, the passageof the terminals through the channels in the block L guards them fromaccidental contact with any metallic part.

" passage of said terminal sert in said core adjacent to and channeledto receive said terminal portion of the-resistor. 2. In an electricallyheated instrument, the combination with i a cylindrical: metallie theflange said were and extending outward through the channel in saidblock.

5. In an electrically heated insulator, the combination with acylindrical core member having a flange at one end thereof and providedwith a central recess extending through said flange and into thecylindrical portion of the core, of an insulator block insert in saidrecess fashioned to be complementary to said cylindrical portion. andflange and provided with a channel extending through portion thereof, awrapping of incore member having aflange at the end theresulatingmaterial surrounding the core and of, of an insulator wrappingsurrounding complementary portion of the block, a re said core andextending ad acent to said: sistor wound upon said wrapping and foldedflange, a resistor wound about and having a. terminal portion extendingoutward longitudinally of said core, and an insulator blockinsert insaid core forming a complementary portion of the cylindrical portion andflange and channeledufor the portion of the resistortheretlirough. p i-3. In an electrically heated instrument, the combination with acylindrical metallic core having a flange at one end thereof and havinga central recess extending from=the end of the core through said flangeand into said'cylindrical portion, an insulator 'block insert withinsaid recess'forming complementary portions of said cylindrical portionofthe core and fian e and provided with a.

channel extending through the flange portionthereof, a wrapping ofinsulating material surroundin said core and complementary portion ofthe insulator block, and a resistor wound upon said wrapping andextending outward through the channel in said insulator block.

'4. In an electrically heated insulator, the combination with acylindrical metallic core having a flange at the end thereof andprovided with a central recess extending to said flange and into thecylindrical portion, of an insulator block in said recess fashioned tobe complementary to the cylindrical portion of said core and also ofsaid flange, said block having a channel extending through the flangeportion thereof outward and inclined towards the center or axis of theblock, means for holding said block in said recess, and an insulatedresistor wound on said wrappingirto extend at substantially right anglesaxi to ally outward, said fold being located over said insulator blockand the outwardly'exv tending portion passing through the channel 1 insaid block.

- 6 In an electrically heated instrument, the combination with acylindrical core member having a flange at one end thereof and proz;videdwith a central recess extending through said flange and into thecylindricalportion, :of an insulator block in said recess formed to becomplementary to said cylindrical portion and flange and channelsextending through the flange portion of said block on diametricallyopposite sides thereof and inclined towards the longitudinal axisthereof, means for securing said block in said core, a wrapping ofinsulating material surroundiug said core and complementary portion ofthe block, a resistor wound upon said insulating wrapping and having theopposite terminal portions thereof folded to pass out- \va'rd throughthe channels in said block, said folds beingadjacent to the portion ofthe block complementary to the cylinder.

7. In an electrically heated instrument, the combination with acylindrical metallic core member, of an insulator surrounding said core,a resistor upon said insulator and having a terminal portion extendingoutward longitudinally of the core, and an aperture-d insulator blockinsert forming a complementary portion of said core.

In testimony whereof we allix our signatures.

FhANK KUllN. LAWRENCE H. THOMAS.

